Veg I do 16+ but 16/8 is a good start point for you. It will help with watering and growth. They do grow on 12/12 but not as fast but some so 12/12 start to finish ok. If it's a hot country night time might be cooler for lights but it shouldn't matter that much.
There is a lot of basics to digest, light, watering, daylight hours, repotting and eventually fertiliser but you've done well to pay attention and get this far. It is simple but some practice.
I would hope is was just watering and light, it perks up and then takes off again.